Location: Vegetable Research
Project Number: 6080-22000-030-000-D
Project Type: In-House Appropriated
Start Date: Sep 1, 2020
End Date: Aug 31, 2025
Objective:
1. Develop and enhance germplasm for host plant resistance of sweetpotato and watermelon that are resistant or tolerant to economically important pests, including whiteflies and soil dwelling pests.
1.A. Develop and characterize watermelon germplasm with resistance to whiteflies and incorporate the resistance into advanced breeding lines.
1.B. Develop sweetpotato germplasm clones that are resistant to soil dwelling pests and have desirable horticultural traits.
2. Assess whitefly-virus-host plant interactions and effects of biotic and abiotic factors on vegetable pests and their biological control agents.
2.A. Determine the effect of biotic and abiotic factors on populations of whiteflies and biological control agents of whiteflies in vegetable production systems.
2.B. Assess the impact of biotic and abiotic factors on whitefly:host-plant:virus interactions and whitefly endosymbionts.
3. Develop new or improved methods for the management of insect pests (including whiteflies and soil dwelling pests) and whitefly-transmitted viruses in vegetable crop production systems.
3.A. Identify and characterize genomics factors and develop novel genomics-based biotechnologies that would impede virus acquisition and transmission from whiteflies to plants.
3.B. Characterize genetic diversity and population structure of the sweetpotato weevil within the U.S.
3.C. Characterize infochemicals and plant-based chemicals affecting vegetable pests (e.g., click beetles, sweetpotato weevil and whiteflies) for use in detection, monitoring, and biologically-based management.
3.D. Identify and characterize sources of pickleworm resistance in cucumbers.
4. Develop sweetpotato germplasm lines adapted to low input, sustainable production systems, especially lines that are productive under weed competition.
4.A. Identify and characterize sweetpotato germplasm that is tolerant/competitive with weed pressure within sustainable production systems.
Approach:
Conduct laboratory, greenhouse, and field experiments to identify sources of resistance and evaluate genetic populations to determine resistance against the sweetpotato whitefly in watermelon, against soil insect pests, weeds and whitefly-transmitted viruses in sweetpotato, and resistance against pickleworms in cucurbits. Assay chemical and physical mechanisms of resistance to pests using tools including gas chromatography-mass spectrometry (GC-MS), and Y-tube olfactometers. Use PCR-markers and other genomic technologies, such as genotype by sequencing, to identify sequences linked to the studied characters and to locate controlling genes on linkage maps. Cross appropriate germplasm to facilitate the incorporation of resistance into advanced breeding lines or new cultivars. Assess the competitive advantage against weeds of sweetpotato genotypes with more vigorous growth habits in comparison to less competitive conventional cultivars, identify competitive genotypes with good horticultural quality, and evaluate them as a component in integrated management systems for conventional and organic growers. Use a recurrent mass selection breeding approach to generate sweetpotato clones with high levels of resistance and good horticultural characteristics. Continue ongoing searches for new resistances or tolerances among watermelon and sweetpotato accessions from the U.S. Plant Introduction System and other collections. Investigate the influence of climate and biotic factors on insect populations and secondary endosymbionts and virus transmission by using field and controlled environments. Study the epidemiology of whitefly-transmitted viruses using biological assays and molecular techniques. Infochemicals used by vegetable pests in mate- and host-finding will be assessed using chemical, electrophysiological and behavioral studies for pests such as click beetles. Make improved plant germplasm available for use by the vegetable industry.
